Along with the recent progress in network technology, the number of mobile terminal devices, as well as the base stations, have increased, resulting in a sharp increase in volume of wireless communication transmitted and received on the network. Accordingly, a multiple input multiple output (MIMO) communication method, in which a plurality of antennas are utilized at the same time, and beam forming with an antenna array including a plurality of antenna elements aligned with an interval between each other, have come to be adopted in the wireless communication device. Further, the number of antennas incorporated in the wireless communication devices of the mobile communication base stations is increasing, and also the number of communication circuits and baseband circuits connected to the antenna is increasing. Because of such increase in number of antennas and in number of circuits, the wireless communication devices have come to generate a larger amount of heat, which leads to an increase in size of radiators and heat exchangers for cooling the antenna and the circuit.
Antenna devices including a plurality of antennas, as well as antenna devices configured to dissipate heat, have conventionally been developed. Patent Literature (PTL) 1 discloses an active antenna system wireless module including an antenna reflecting plate having a heatsink. PTL 2 discloses an antenna device for a mobile communication system base station, in which a circuit substrate having electronic parts mounted thereon, antenna elements, and a reflecting plate are provided in a radome, with a structure that efficiently emits heat from the electronic parts to outside the radome. PTL 3 discloses an antenna including a reflecting plate and a radiator element, the radiator element having an array structure including a plurality of pairs of dipole antenna elements. PTL 4 discloses an antenna device in which electronic parts are mounted inside an elongate cover having a plurality of vent holes, to prevent an excessive increase of the temperature of the cover. PTL 5 discloses a dual-frequency dual-polarization antenna for a mobile communication base station, including a first radiator element module for a first frequency band and a second radiator element module for a second frequency band, the second radiator element module including a plurality of cross-shaped dipoles.